Tufte-isms

Image: Greg Mably
Graphical excellence is that which gives to the viewer the greatest number of ideas in the shortest time with the least ink in the smallest space. —Edward R. Tufte

We live in an age characterized by PowerPointlessness , where Microsoft PowerPoint presentations are not only ubiquitous but laden with sounds and transitions that have no discernible purpose.

It's an age of the triple delivery, where presenters hand out text, display it on the screen, and then read it aloud. It's an age, too, of the charticle, a news article that consists of a graphic with a depressingly small amount of explanatory text.

The sad irony here is that as information overload has gone from a theoretical concept to an all-too-present reality, information formats designed to reduce that overload, such as presentations and newspaper articles, are increasingly dumbed down and lacking in substance.

My purpose here isn't so much to examine Tufte's ideas and measure his considerable influence but to see how those ideas and his influence have shaped the language. Tufte, it turns out, is not only a doyen of data visualization but also a neologist par excellence who has coined a number of memorable and useful terms.

Tufte's most famous coinage might be chartjunk, which refers to chart elements that not only serve no purpose but may in fact hinder understanding. "Credibility," Tufte notes, "vanishes in clouds of chartjunk." In Tuftese, when chartjunk takes a cartoonish form (for example, increasingly tall piles of dollar bills to illustrate rising prices) the result is a chartoon.

Tufte has famously said that when it comes to the visual display of information, "above all else show the data." So one of the key principles in good information design is to shoot for a high data-ink ratio, which is the ratio of data-ink (the elements that convey the actual data) to the total ink used in the graphic. To calculate this, first distinguish the data-ink from the redundant data-ink (data elements repeated unnecessarily) and the non-data-ink (elements that are used ostensibly to support the data, such as grid lines, axes, labels, and legends, or as decoration, such as background colors, data markers, and of course, chartjunk). "Ink" here refers to both text and graphical elements.

Similarly, Tufte counsels that the representation of numbers in a graphic should be proportional to the actual values of the numbers, and he tellingly calls this ratio the lie factor, because if the visual representation of an effect is much larger than the actual effect, then the graphic is lying about the data.

When you eliminate or at least minimize the redundant data-ink, non-data-ink, and any other non-information and keep the lie-factor ratio around 1, you increase the overall information density (or data density) and ensure that your design isn't data-thin or otherwise an example of disinformation design.

Tufte also introduced the world to small multiples, a data visualization that uses multiple versions of the same image or chart to illustrate different aspects of a data set. He was also the inventor of the sparkline, a small, simple word-size infographic designed to be displayed in line with text.

The goal, in short, is to use analytical design to increase information resolution (the paradoxical design strategy that when you need to clarify something, add more detail) and make information quantitatively eloquent. How does all this help us as we try to navigate a world drowning in data? Appropriately, I'll let Professor Tufte have the last word: "There is no such thing as information overload. Only bad design."